Rotating electrical machine such as an alternator adaptable to different types of motor vehicles engines

ABSTRACT

A rotary electrical machine such as an alternator, in particular for a motor vehicle. This machine is adaptable to various types of motor vehicle engine and comprises removable lugs ( 16 ) for fixing the machine to a fixed support such as a support secured to the vehicle engine and which are able to be mounted on the peripheral face of at least the front bearing ( 2 ), each between two lateral support faces ( 14 ) provided on this peripheral surface at a predetermined distance from each other in the peripheral direction of the bearing. The lateral support face ( 14 ) is formed by the lateral face of an area of protruding material ( 12 ), which constitutes an alternator assembly area, and the fixing lug ( 16 ) is disposed between two lateral support faces ( 14 ) opposite each other and belonging to two adjacent protruding areas ( 12 ).

TECHNICAL FIELD OF THE INVENTION

The invention concerns a rotary electrical machine such as analternator, in particular for a motor vehicle, adaptable to variousmotor vehicle engines, of the type comprising a casing enclosing astator and a rotor whose spindle is supported by front and rear bearingsand carries a pulley driven by means of a belt and removable fixing lugsable to cooperate with a support fixed to the vehicle engine, and whichare able to be mounted on the peripheral face of at least the frontbearing, each between two support faces provided on this peripheral faceat a predetermined distance from each other in the peripheral directionof the bearing.

PRIOR ART

Alternators of this type are already known. Their main field ofapplication is the-automobile market relating to spare parts, that is tosay replacement parts, and small production runs. This is because, byvirtue of their removable fixing lugs, alternators are adaptable tovarious types of motor vehicle engine.

French patent application N^(o) 2 793 300 describes an alternator asindicated above, in which there is machined, in a protruding area on theperipheral surfaces of the front and rear bearings, a dovetail groovewhich extends parallel to the axis of the two bearings and which isintended to receive two fixing lugs.

These lugs are able to be moved by sliding in this groove and can beimmobilised therein at an axial distance from each other by clampingscrews passing through holes formed in the lateral walls of the dovetailgrooves. The front bearing is also configured so as to allow themounting in various angular positions of a lug for tensioning the drivebelt. For this purpose, the front bearing comprises a peripheral rib inthe form of an arc of a circle and, in front of the lateral face of thisrib, which is oriented towards the pulley and extends radially, an axialsupport face for the tensioning lug. This lug can be moved angularly onthis support face and can be immobilised in various angular positions byscrews passing through the lug and engaging in threaded holes in theradial rib face.

Because of their single dovetail groove in the bearings, the alternatorknown through this French patent has the major drawback of not beingable to allow a choice of the relative position of the rear connections,which is becoming more and more critical because of the constraints oflocation and size of the alternators in their environment. According tothe vehicle, the position of the B⁺ output terminal of the alternatormay have a different angular position.

The peripheral rib in the form of an arc of a circle of theaforementioned known alternator constitutes a known obstacle toproducing several protruding areas regularly distributed angularly onthe external periphery of the front and rear bearings of the alternator.

The aforementioned alternator also has the drawback of not allowingpermutation of the fixing lugs with the belt tensioning lug. This isbecause the fixing lugs inserted in the groove in the protrusion aredesigned to bear the major part of the weight of the alternator whilstthe belt tensioning lug is carried by the peripheral rib in the form ofan arc of a circle, not designed to bear the weight of the machine bymeans of fixing lugs. Thus the alternator described in theaforementioned patent application can find an application only foralternators necessarily comprising at least one belt tensioning lug.This alternator can therefore not be used for motor vehicles in whichthe alternator does not have a belt tensioning lug but only three orfour fixing lugs. In this case, a device external to the alternatoreffects the tensioning of the belt.

OBJECT OF THE INVENTION

The aim of the present invention is to propose an alternator of the typeindicated above which mitigates the drawbacks of the known alternatorswhich have just been stated and is adapted to the many applications inthe field of motor vehicles, required by the market consisting ofreplacement parts and short production runs.

For this purpose it proposes a rotary electrical machine such as analternator, in particular for motor vehicles, adaptable to various typesof motor vehicle engines and comprising a casing enclosing a stator anda rotor whose spindle is supported in front and rear bearings andcarries a pulley for driving by means of a belt, and removable lugs forfixing the machine to a fixed support such as a support secured to thevehicle engine and which are able to be mounted on the peripheral faceof at least the front bearing, each between two lateral support facesprovided on this peripheral surface at a predetermined distance fromeach other in the peripheral direction of the bearing, in which anaforementioned lateral support face is formed by the lateral face of anarea of protruding material on the external peripheral surface of thebearing, and in that an aforementioned fixing lug is disposed betweentwo lateral support faces opposite each other and belonging to twoadjacent protruding areas.

Thus the invention proposed makes it possible to choose the relativeposition of the rear connections of the alternator in order tofacilitate its connection in the motor vehicle. The invention also hasthe advantage of offering the possibility of choosing the location whereit is wished to put the fixing lugs on the external peripheral surfaceof the bearing. Another advantage according to the invention consists ofoffering the possibility of using only fixing lugs or again using fixinglugs in combination with at least one belt tensioning lug.

The invention is advantageously supplemented by the various followingcharacteristics, taken alone or in all their technically possiblecombinations:

-   -   the two lateral support faces and the peripheral surface portion        of the machine, between the two lateral faces, constitute a        runner for receiving and positioning a fixing lug,    -   a protruding area is formed by an area serving for assembling        the machine,    -   an aforementioned bearing carries on its external peripheral        surface a multitude of protruding areas delimiting a plurality        of runners advantageously distributed equidistantly,    -   a fixing lug comprises a base part by means of which the lug        engages in the positioning runner and a top part for fixing to        the aforementioned fixed support,    -   a fixing lug is produced in the form of a single piece whose        base and top parts are constituent parts,    -   the base and top parts are separate pieces, able to be assembled        for forming a fixing lug,    -   a fixing lug is fixed in its positioning runner by a clamp        device bearing through one part on the base of the fixing lug        and through another part on the adjacent protruding area,    -   the base of the fixing lug has a width less than the width of        the runner intended for receiving it and in that the fixing        clamp device comprises an element in the form of a wedge which        engages in the gap created when the base is pushed in abutment        against the other support face and provides by a wedging effect        the immobilisation of the base in its runner when the fixing        screws are tightened,    -   the clamp device has the general shape of an L, one arm of which        forms the aforementioned wedge element whilst the other arm        comes into abutment on the protruding area of the periphery of        the bearing,    -   the clamp device comprises a piece forming a separate wedge and        a clamping plate coming into abutment on the protruding area and        the piece forming a wedge,    -   the clamp device comprises a piece forming a wedge of        trapezoidal shape and a clamping plate coming into abutment on        the base of the lug and the protruding area and in that the        wedging effect is produced by a clamping screw passing through        the plate and the wedge piece and during tightening drawing the        wedge piece towards the plate,    -   the clamp device comprises a clamping plate, part of which comes        into abutment on the protruding area whilst another part comes        into abutment on an inclined surface forming a ramp configured        so as to produce a force pushing the base of the clamp against        the opposite runner support face when the plate part is clamped        against the protruding area,    -   a lug base has, in the plane of its receiving runner, the        general shape of a U so as to leave free, in its central part,        the ventilation holes formed in the peripheral wall of the        bearing,    -   a lug base comprises an aperture for leaving free the        ventilation holes formed in the peripheral wall of the bearing,    -   the surface portions of the clamp device and of the fixing lug        base which are in abutment on each other are notched, the        notches advantageously extending perpendicularly to the axis of        the machine in order to improve the axial immobilisation of the        fixing lugs,    -   the face for placing the base of a fixing lug on the peripheral        surface of the bearing has a curvature corresponding to that of        the surface portion of the bearing surface between the two        lateral support faces.

SUMMARY DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will emergeclearly from the description which is given below, by way of indicationand in no way limiting, with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective view of the casing of an alternator according tothe invention;

FIG. 2 is a view in the direction of the arrow II in FIG. 1;

FIGS. 3 to 6 are schematic views, similar to FIG. 2, of four versions ofan embodiment of the mounting of a removable fixing lug according to theinvention;

FIG. 7 is a detail view, to a larger scale, of the area encircled at VIIin FIG. 5;

FIG. 8 is a detail view, to a larger scale, of the area encircled atVIII in FIG. 6;

FIG. 9 is a perspective view of a variant embodiment of a fixing lugaccording to the invention;

FIG. 10 is a view to a larger scale of the part indicated at X in FIG.1.

DESCRIPTION OF PREFERENTIAL EMBODIMENTS OF THE INVENTION

FIG. 1 shows a casing designated by the general reference 1 of analternator for a motor vehicle. This casing encloses, in a manner knownper se, a stator and a rotor and associated devices. The alternatorstructure, inside the casing, will not be described in more detail sincethe invention does not relate to it.

The casing 1 is formed by the assembly of front 2 and rear 3 bearingsintended, in a manner known per se, to support the spindle of thealternator rotor.

As shown in particular in FIG. 1, each bearing has a conventionalconfiguration, that is to say it has the form of a cup comprising acylindrical peripheral wall 5 and a bottom wall 6 at the centre of whichis situated the passage orifice 7 for the rotor shaft, surrounded by aring of passage orifices 8 for the flow of a cooling fluid. In theperipheral part 5 and the adjacent part of the bottom 1 there are formedfour series of lateral holes 9 for discharge of the cooling fluid.

The bearings also carry, on their cylindrical peripheral face 5,distributed angularly in an equidistant fashion, four areas ofprotruding materials 12, which advantageously constitute the assemblyareas for the alternator through which there pass the tie rods intendedto fix the front and rear bearings. An assembly area can also, wherenecessary, be intended for fixing the stator. These protruding areas 12extend parallel to the axis of each bearing and the areas 12 of onebearing are aligned with the areas 12 of the other. Thus, by using thepre-existing assembly areas, the radial ventilation holes are notobstructed, which guarantees optimum cooling of the alternator.

According to an essential aspect of the invention, these protrudingareas 12 are used to make the casing 1 and thus the alternator adaptableto various types of motor vehicle engine. As shown in particular byFIGS. 3 to 6, for this purpose the lateral faces 14 of the protrudingareas 12 are configured so as to be able to position, between theopposite faces 14 of two adjacent protruding areas 12, a lug 16 forfixing the casing to a support of the motor vehicle engine or directlyto this engine. It should be noted that the lugs 12 can be used eitheras fixing lugs or as lugs for tensioning the belt driving theconventional pulley, known per se and therefore not depicted.

As can be seen in the figures, a lug 16 according to the invention whichis thus removable is composed of a base part 17 and a top part 18. Thebase part 17 provides the interface with the bearing and is intended toengage in the corresponding two lateral faces 14 of the two protrudingareas 12 adjacent to the periphery of the bearing. The face 20 forplacing the base 17 of the lug on the peripheral surface 5 of thebearing has a curvature corresponding to that of the surface portion 21of the surface 5 between the two lateral support faces 14. The baseenables the lug to slide in the runner formed in the portion of theperipheral face 21 of the bearing and of the two lateral faces 14 of thetwo protrusions 12. The base 17 comprises, for its final fixing, notchedlines, depicted at 24 in FIG. 10, perpendicular to the axis of thealternator, on the top of the base cooperating with fixing members 12which are described below. The length, in the axial direction, of thesliding base 17 of the lug depends on the axial offset of the lug, ascan be seen in FIG. 1, but must allow secure final fixing of the lug onthe bearing and at the same time leave clear the outlet holes 9. Asshown in FIG. 1, the lug base 17 can have, in the plane parallel to therunners, a U-shaped profile, the external edges of the arms cooperatingwith the support faces 14. By virtue of this profile, the holes 9 canremain clear.

FIG. 9 illustrates a variant embodiment of a fixing lug 16 according tothe invention. In this case, the lug base 17 is provided with anaperture 42 which leaves the holes 9 clear.

The top part 18 of a lug 16 provides the interface with the engine ofthe motor vehicle. It is provided with a hole 19 for fixing it to thesupport of this engine, circular in shape for the fixing lugs asdepicted in FIGS. 1, 2, 9 or 10, or oblong for the belt tensioning lugsas depicted in FIGS. 3 to 6. Naturally the shape of the holes 9 for thefixing or belt tensioning lugs can have shapes different from thosedescribed above. Thus, for example, the belt tensioning lugs can alsohave threaded or smooth circular holes 19. The lug may be different fromone application to another according to the angular position, the heightof the axis, the diameter of the bore and the thickness of its hub,which makes it necessary to have available a certain number of differentlugs for covering the various cases of application. It should be notedthat the lugs of the front and rear bearings are interchangeable andthat the base and top parts may belong to the same piece or be twopreassembled pieces.

The adjustment of the position of a fixing lug 16 or a belt tensioninglug in its runner and its final fixing in the appropriate position onthe support bearing is effected by means of a clamp 22 which is placedso as to laterally cover the lug 15 to be fixed on the part of thebearing external to the cover, that is to say the external surface ofthe protruding area 12 in the vicinity of the runner. The clamp is fixedto the bearing by means of at least one screw 23 located in threadsformed in the protruding area 12. Advantageously there may be a notchedarea. The internal surface of the part of the flange which comes intoabutment on the notched area 24 on the top of the lug base 17 is notchedas indicated at 26 in FIG. 10, so as to correspond to the notches on thebase. The coinciding of the notched parts of the lug and flange isfacilitated by a clearance or an oblong shape of the holes in the clamp,making it possible when a screw is tightened to slightly move the clamp.Thus the lug will also be positioned exactly at the required place. Inthis way the axial immobilisation of the fixing lugs is ensured.

FIGS. 3 to 6 show four possibilities of a fixing of a lug 16 in a runnerof a front or rear bearing.

In the solution depicted in FIG. 3, the two lateral faces 14 of therunner form an angle α with the bottom 21 of the runner, which is lessthan or equal to 90°.

The two lateral faces 25 of the base 17 of the lug 16 have aninclination corresponding to that of the faces 14, but the width of therunner of the bearing is greater than the width of the base 17. Thus,when the lug is placed in its runner, one lateral face 25 is pressed ona support face 14 of the bearing. However, on the other hand, thereexists a clearance 27 for example of several millimetres between theother lateral face 25 of the base and the corresponding support face 14of the runner.

In order to fix the base 17 of the lug 16 in the bearing runner, a clamp22 is used which has on one side a projecting portion in the form of awedge 28 which engages in the gap 27 between the two separated faces 25and 14 and, by a wedging effect, ensures the locking of the base 17 ofthe lug 16 in the runner when the screws 23 are clamped. According toits length, the clamp can comprise an appropriate number of fixingscrews. Advantageously, the orientation of the screws is not radial andthe axis of the screws forms with the peripheral surface of the tangentto the surface of the protrusion 12 on the side opposite to that of theface 14 an angle of less than 90°.

Advantageously, according to another embodiment of the invention, thetwo faces 14 of two adjacent protrusions 12 form a runner for a fixinglug 16 having different angles. On the one hand, the angle α, previouslydescribed, formed by the lateral face 14 of the runner with the bottom21 of the runner is less than 90° for the side of the runner opposite tothat carrying the flange 22 and, on the other hand, the angle α formedby the side of the runner carrying the flange 22 is equal to or lessthan 90°. The face 14 cooperating with the fixing flange 22 has aroughly radial, or even radial, direction, which has the advantage ofradially guiding the flange 22 well when the screws 23 are screwed andthus improving the locking of the fixing lug 16 by better abutment ofthe clamp 22 on the face 25 of the facing lug 16.

Advantageously, whatever the embodiment, the two lateral faces 25 of thebase 17 of the lug 16 have an inclination corresponding to that of theface 14 opposite to that carrying the clamp. Thus it is possible toinsert the fixing lugs in the groove indifferently in one of the twopossible directions in the axial direction of the groove.

Advantageously, the material used for producing the clamp is a sinteredsteel which has the characteristic of being of low elasticity andeconomical.

The fixing solution depicted in FIG. 4 corresponds in its principle tothe solution depicted in FIG. 3. The only appreciable difference lies inthe fact that the part of the wedge 28 is now formed by a separate piece30 which will be pushed into the gap 27 by a clamp plate 31, when thescrews 23 are tightened.

Fixing by means of a wedge has the advantage that there is added to thefixing by pressure a lateral component due to the wedging forcesexerted. Advantageously, the material used for the form of the wedgeclamp incorporated could be based on steel, and hence there will resulta smaller space requirement than with a choice of material made fromaluminium alloy.

FIG. 5 illustrates a method of fixing by means of a clamp 22 in the formof a plate 35 which cooperates with a member in the form of a wedge witha trapezoidal cross-section 32, as can be seen in more detail in FIG. 7.In this embodiment, the lateral support surface 25 of the lug base 17 onthe same side as the application of the clamp plate 35 has aninclination which is opposite to that of the support face 14 of therunner. When it is wished to position the lug 16 in its runner, thelateral face 25 of the lug base 17 and the corresponding support face 14of the runner are put in abutment on one side and the trapezoidal-shapedpiece 32 is inserted in the gap between the other pair of faces 25 and14. The piece 32 comprises two threaded holes each intended to receive aclamping screw denoted 36 which passes through the clamp 22 andtherefore the head 36 bears on the top face of the clamp. When thescrews 36 are tightened, the trapezoidal piece 32 which is captive tendsto rise up and wedge between the faces 25 and 14. The result is animmobilisation and securing of the lug in its runner.

FIG. 6 illustrates one advantageous fixing mode. According to this mode,one face of the runner indicated by the specific reference 14′, insteadof being inclined like the support faces 14, forms a right angle withthe bottom of the runner at this point, that is to say extendssubstantially radially, as shown by the figure. The correspondinglateral face 25′ of the lug base 17 has the same orientation as the face14′. The edge of the lug base 17 along the base 25′ has an inclinationand constitutes a lateral thrust ramp 38. The clamp device 22 inaddition to the ramp 38 has a plate 39 angled in an appropriate fashion,which rests through an arm 40 on the external area of the runner andthrough its inclined arm 41 on the ramp 38. When the arm 39 in abutmenton the bearing is clamped by the clamping screws 23 against the surfaceof the bearing, the arm 40 in abutment on the ramp 38 pushes the base 17of the lug 16 in its runner on the opposite support face 14.

The fixing mode according to FIG. 6 has the advantage that the lug thusfixed will be wedged in its runner housing. The material of the clampcould be different from that of the bearing, if that proved necessaryfor its resistance to the forces. The opposite faces of the flange andlug could have serrations which would afford a better resistance toaxial sliding.

It is clear from the above description that, by virtue of the systemsfor fixing the removable lugs which have just been described, theinvention makes it possible to use alternators from conventional massproduction for various types of motor vehicle. The invention makes itpossible to adapt such an alternator to a given type of motor vehicleengine simply by locating fixing lugs in one or more runners angularlydistributed around the front and/or rear bearings, by pivoting, perquarter in the case described of four runners, of the position of theelectrical terminals and by appropriate axial positioning of the lugs intheir runner. By virtue of the notching of the cooperating services, afixing on lugs in their runner is obtained.

Naturally various modifications can be made to the invention asdescribed above and depicted in the figures. Thus the number ofprotrusion areas on the periphery of the bearings and thus the number ofrunners could be different from four. It could also be envisaged fixingthe lugs directly to the bearing by providing oblong holes in the partsor shrinking them on after positioning in their positions.

The invention particularly finds an advantage in the industry of thereconditioning of alternators of all origins allowing standard exchangeconsisting of making a worn appliance operational once again afterhaving restored it, for example by cleaning, machining or replacingdefective components. Thus a renovated electrical machine according tothe invention allows the reconstruction of electrical machines which maybe dedicated to applications other than the original ones. Thiselectrical machine according to the invention makes it possible toreduce stocks at motor vehicle repairers since one and the same machinecan be dedicated to several types of motor vehicle rather than limitedto a single original application.

These alternators produced according to the invention thereforeconstitute “multi-application alternators”.

Multi-application alternators can be equipped with magnetic circuits andregulation and rectifying systems making it possible to supply thevoltage currently in use on 14-volt cars but also all other voltagessuch as 6, 28 or 42 volts. Likewise these alternators could supplydirect or alternating current and fulfil all the additional functionsassociated with the voltage regulator.

Multi-application alternators, new or reconditioned, can be cooled byair or by a cooling liquid. Alternators cooled by air according to theinvention are provided with internal or external ventilation.Alternators cooled by a cooling liquid comprise, in a manner known perse, double walls allowing the circulation of the cooling liquid. In thiscase, the holes for fixing the clamps will be blind rather than openingout.

1. Rotary electrical machine, adaptable to various types of motorvehicle engines and comprising a casing enclosing a stator and a rotorwhose spindle is supported in front and rear bearings and carries apulley for driving by means of a belt, and removable lugs including abase part (17) and a top part (18) which are able to be mounted on theperipheral face of at least one of the bearings, each lug between twolateral support faces provided on this peripheral surface at apredetermined distance from each other in the peripheral direction of atleast one of the bearings, wherein an aforementioned lateral supportface (14, 14′) is formed by the lateral face of an area of protrudingmaterial (12) on the external peripheral surface of at least one of thebearings, and wherein said base part (17) of said lug (16) is disposedbetween two lateral support faces (14, 14′) opposite each other andbelonging to two adjacent protruding areas (12), and wherein the twolateral support faces (14, 14′) and the peripheral surface portion (21)of the machine, between the two lateral faces, constitute a runner forreceiving and positioning said lug (16), and wherein at least one of thebearings (2, 3) carries on its external peripheral surface a multitudeof protruding areas (12) delimiting a plurality of runners; and whereinthe lug (16) is fixed in its positioning runner by a clamp device (22)bearing through one part on the base (17) of the fixing lug (16) andthrough another part on the adjacent protruding area (12).
 2. Rotaryelectrical machine according to claim 1, wherein a protruding area (12)is formed as an assembly area for the alternator.
 3. Rotary electricalmachine according to claim 1, wherein said plurality of runners aredistributed equidistantly.
 4. Rotary electrical machine according toclaim 1, characterised in that by means of the base part (17) the lugengages in the positioning runner and said top part (18) for providingan interface with the engine of the motor vehicle.
 5. Rotary electricalmachine according to claim 4, wherein the lug (16) is produced in theform of a single piece whose base (17) and top (18) parts areconstituent parts.
 6. Rotary electrical machine according to claim 4,characterised in that the base (17) and top (18) parts are separatepieces, able to be assembled for forming the lug (16).
 7. Rotaryelectrical machine according to claim 1, characterised in that the base(17) of the lug (16) has a width less than the width of the runnerintended for receiving it and in that the clamp device (22) comprises anelement in the form of a wedge (28, 30, 32) which engages in a gap (27)created when the base (17) is pushed in abutment against the othersupport face (14) and provides by a wedging effect the immobilization ofthe base in its runner when the fixing screws (23) are tightened. 8.Rotary electrical machine according to claim 7, characterised in thatthe clamp device (22) has the general shape of an L, one arm of whichforms the aforementioned wedge element (28) whilst the other arm comesinto abutment on the protruding area (12) of the periphery of thebearing.
 9. Rotary electrical machine according to claim 8,characterised in that the clamp device (22) comprises a piece forming aseparate wedge (30) and a clamping plate (31) coming into abutment onthe protruding area (12) and the piece forming a wedge (30).
 10. Rotaryelectrical machine according to claim 8, characterised in that the clampdevice (22) comprises a piece forming a wedge (32) of trapezoidal shapeand a clamping plate (35) coming into abutment on the base (17) of thelug (16) and the protruding area (12) and in that the wedging effect isproduced by a clamping screw passing through the plate and the wedgepiece (32) and during tightening drawing the wedge piece (32) towardsthe plate.
 11. Rotary electrical machine according to claim 8,characterised in that the clamp device (22) comprises a clamping plate(39), part of which (40) comes into abutment on the protruding area (12)whilst another part (41) comes into abutment on an inclined surfaceforming a ramp (38) configured so as to produce a force pushing the base(17) of the clamp (16) against the opposite runner support face (14)when the plate part (48) is clamped against the protruding area (12).12. Rotary electrical machine according to claim 1, characterised inthat a lug base (17) has, in the plane of its receiving runner, thegeneral shape of a U so as to leave free, in its central part, theventilation holes (9) that are formed in the peripheral wall of at leastone of the bearings.
 13. Rotary electrical machine according to claim 1,characterised in that a lug base (17) comprises an aperture (42) forleaving free the ventilation holes (9) that are formed in the peripheralwall of at least one of the bearings.
 14. Rotary electrical machineaccording to claim 1, characterised in that the surface portions of theclamp device and of the lug base (17) which are in abutment on eachother are notched (24, 26), the notches advantageously extendingperpendicularly to the axis of the machine in order to improve the axialimmobilization of the lugs (16).
 15. Rotary electrical machine accordingto claim 4, characterised in that the face (20) for placing the base(17) of the lug (16) on the peripheral surface of at least one of thebearings has a curvature corresponding to that of the surface portion(21) of the bearing surface (5) between the two lateral support faces(14).